资源加载

方式一：使用全局变量，以拖动的方式赋值

public class Main : MonoBehaviour
{
    public TextAsset indexJson;
    ...

方式二：新建Resources文件夹

把资源文件放在该文件夹下，例如index.json这个文件，加载的时候只需要写成index，不需要带着后缀名。 Resources文件夹可以位于Assets文件夹的任意位置。

    var x = Resources.Load<TextAsset>("index");
    Debug.Log($"resource .length={x.text.Length}");

方式三：网络加载资源

        var t = await Util.GetRemoteTexture("https://forum.unity.com/data/avatars/m/628/628421.jpg?1441745369");
        var obj = new GameObject();
        obj.AddComponent<RawImage>();
        var rawImage = obj.GetComponent<RawImage>();
        rawImage.texture = t;

使用网络请求获取资源

    public static async Task<Texture2D> GetRemoteTexture(string url)
    {
        using (UnityWebRequest req = UnityWebRequestTexture.GetTexture(url))
        {
            req.certificateHandler = new BypassCertificate();
            // begin request:
            var asyncOp = req.SendWebRequest();

            // await until it's done:
            while (asyncOp.isDone == false)
                await Task.Delay(1000 / 30); //30 hertz

            // read results:
            if (req.result == UnityWebRequest.Result.ConnectionError || req.result == UnityWebRequest.Result.ProtocolError)
            {
                Debug.Log($"{req.error}, URL:{req.url}");
                return null;
            }
            else
            {
                // return valid results:
                return DownloadHandlerTexture.GetContent(req);
            }
        }
    }

方式四：通过AssetDatabases加载资源

        {
            //使用AssetDatabase加载图片，图片的位置可以比较随意
            var x = AssetDatabase.FindAssets("PICODeveloper");
            Debug.Log($"assets:{string.Join(",", x)}");
            if (x.Length > 0)
            {
                var assetId = x[0];
                var filepath = AssetDatabase.GUIDToAssetPath(assetId);
                texture = AssetDatabase.LoadAssetAtPath<Texture>(filepath);
            }
        }